禽源大肠杆菌的分离及其毒力因子的检测

Isolation of avian Escherichia coli and PCR detection of their F1 and HPI genes

摘要:

从临床疑似大肠杆菌感染的病禽组织中分离到69株细菌(其中鹅源29株,鸡源40株);通过常规形态学、培养特性和生化特征的研究,确定为大肠杆菌。PCR检测表明,其中46株(66.7%)为F1+大肠杆菌,10株(14.5%)为F1⁺HPI⁺大肠杆菌,2株(2.9%)为HPI+大肠杆菌;通过比较还发现,F1菌毛和HPI在鹅源和鸡源大肠杆菌中以及不同脏器来源的菌株中具有相似的分子流行病学。O抗原鉴定结果表明鹅源大肠杆菌的O抗原型主要有O26、O78、O18、O117,鸡源大肠杆菌的O抗原型主要有O109、O24、O18、O139、O78。药敏试验表明,其中绝大多数菌株对先锋霉素V、呋喃妥因、庆大霉素敏感,对环丙沙星因菌株差异而不同,林可霉素、四环素、多粘菌素多不敏感。

Abstract:

To further investigate into the prevalence of F1 fimbriae and high pathogenicity island (HPI) in avian Escherichia coli，a total of 69 bacteria isolates (29 from geese and 40 from chickens) were obtained from deceased poultry and characterized to be Escherichia coli by gram staining，culture characterizing and bio-chemical testing. Two sets of primers were designed or analyzed with DNAStar software based on the F1 and HPI sequences that deposited in GenBank and synthesized by Sangon Biological Engineering Technology and Service Co. Ltd. (Shanghai，P. R. China). All the primers were tested for their specificities by using reference E. coli strains，and it is confirmed that the PCR using primers F1-F and F1-R could identify F1⁺ E. coli，as well as the PCR using primers irp-F and irp-R could identify HPI⁺ E. coli. All the isolates were submitted to PCR detection，and the data shows 46 isolates (66.7%) were F1-positive，10 isolates (14.5%) were F1⁺HPI-positive and 2 isolates (20.0%) were HPI-positive. Furthermore analysis indicated that the prevalence of F1 and HPI have no different between the isolates from geese and chickens，and no different among the isolates from different tissue，such as liver，lung and duodenum. In addition，all the 69 E. coli isolates serological typed，and the results show that the isolates from geese were belonged to O26(25.0%)，O78(12.5%)，O18(12.5%) and O117(12.5%%)，while E coli from chickens were fell into O109(37.5%)，O24(18.75%)，O18(12.5%)，O139(12.5%) and O78(6.25%). Seven kinds of antibiotics were tested on 11 isolates，and it revealed that most isolates were sensitive to cefazolin，nitrofurantoin and gentamycin，while resistant to lincomycin，tetracycline and polymycin B.